OVERALL OBJECTIVE OF TOTAL PROJECT: The major overall objective remains to further develop and refine equipment for measuring laxity of the knee, both in laboratory specimens and on clinical subjects. Intact normal knee specimens are to be tested in the equipment and the effect of selective cutting of ligamentous structures observed. Knee specimens in which prosthetic designs have been inserted are also to be studied and the effects of removing stabilizing ligamentous structures observed. GOALS SET FOR CURRENT YEAR: 1. Methods for clinical testing for normal and abnormal knees on patients with emphasis on testing the Total Condylar Knee Prosthesis in which the cruciate ligaments are excised. 2. Continued studies of relative importance of ligamentous structures and the static stability of the knee. 3. A study of the dynamic stability of the quadriceps mechanism of the knee. 4. Design apparatus for testing natural and artificial ligaments in dogs.